It is strange how quickly and apparently seamlessly the abnormal fades into the routine. Some New Yorkers who would have struggled to imagine the Manhattan skyline without the twin towers now have difficulty picturing what it looked like on September 10. Similarly the bombing of Afghanistan, which was at first such a shock to the international system, is rapidly becoming a bloody, botched but banal fact of life. Slipping down the news agenda, behind Ireland, cannabis, citizenship lessons, crime and health, it is no longer considered news since little has really changed since the bombing started and the well of indignation from which heated debate has been drawn is not bottomless.

Meanwhile, human narratives that might provoke an intense emotional response are also lacking. There are no mobile phone transcripts of Afghan civilians bidding farewell to their loved ones as the cluster bombs rain down around them, no immediate images of the impact of the wayward missiles on unlucky suburbs. Unlike those who perished in the World Trade Centre, the dead in Afghanistan do not have names, only numbers. And, given the limited access to the area, even those are questionable. Like the continuous bombing of Iraq this assault is becoming just "something we do" - the constant infliction of misery on people in poor, distant lands. And while it is a living nightmare for those on the ground, for a complacent west, which can turn the page or change channel, it can soon be demoted to a running sore.

It is in these challenging circumstances that a peace movement must gather momentum. In Britain it has had a promising start. A 1,000-strong march in Sheffield on Saturday was the largest they have seen since the miners' strike; 70 people at a meeting in Blackburn on Thursday; weekly vigils from Frome to Newcastle. The demonstrations a fortnight ago were larger, more vibrant and confident than even the organisers expected. In London it was not just the size but the composition that was impressive - a mix of races, ethnicities and ages as well as a gender balance rarely achieved in popular protest here. The demonstration planned for November 18 promises to be even bigger. So far so good. But to build a movement that will achieve its ultimate aim - to force an end to the current military action - it will have to go much further.

To rally the faithful is one thing; to win over the waverers quite another. It is a task that will demand attributes that sadly do not come naturally to many on the left: persuasiveness, pluralism, flexibility and sensitivity. The campaign has to start from where people are, rather than where anti-war activists would like them to be. The overwhelming majority of the British public - about 74% - support military action. They do so not because they are warmongers or racists - although there are undoubtedly some among them - but largely because they believe that "something must be done" in response to the terror attacks in New York. Most have so far been presented with only two choices: either bombing Afghanistan or doing nothing.

The anti-war movement must remain clear and unequivocal in its response to September 11. With every call to halt the military action it should continue to condemn the bombing of the World Trade Centre, express sympathy, unconditionally and without qualification, for the victims and join the call to bring those proved responsible to justice. A critical appraisal of American foreign policy offers a context for the attacks but not a justification for them.

Similarly, the movement should aim to be as broad-based and non-doctrinaire as possible. An anti-imperialist critique certainly informs opposition to this war; but it should not be demanded as a prerequisite for those who wish to see an end to it. It is the "stop the war" movement; not stop all wars or stop a war. The movement must keep its eyes on the prize. But while it should be single-minded in its opposition to the bombing of Afghanistan and solid in its response to September 11, it ought to be flexible on just about everything else.

A ll alternatives to the current military action must be aired within it and articulated through it. From those who would like to see firmer evidence against Bin Laden before acting, to some who believe only global poverty is the source of the discontent, it must showcase the range of options that have been put forward. Some back a United Nations military intervention under international law; others want to take up the Taliban's offer of handing Bin Laden over to a third country; many want to put him before an international war crimes court; a few believe only a root-and-branch reform of US foreign policy will work. The anti-war movement should adopt none of these proposals but embrace all of them. It is not its job to be prescriptive about what course of action to take once the bombing has stopped. But to stop the bombing by exposing its futility and inhumanity and the sophistry of those who claim there is no alternative to it.

Finally, it must have confidence in its own potential. A focused, responsive, sensitive anti-war movement can win. Thanks to the anti-globalisation movement and campaigns to defend asylum seekers, the British left starts with a heightened internationalist conscious ness. Efforts to stop the Gulf war came on the back of the poll tax demonstrations; this anti-war movement follows Seattle, Washington and Genoa.

Moreover, the consensus Tony Blair has built at home to support this war is as fragile as the coalition he has helped construct abroad. So far, nearly all of this opposition has come from outside parliament. But dissent among MPs is slowly growing and the larger the movement outside the Commons the more likely those inside will be to follow their conscience (or at least their commonsense) rather than their whips. As the recession continues to bite, people will increasingly question the value of spending millions on a murderous war with neither cogent objectives nor any clear timetable, when we could breathing life into the health service and fighting poverty at home.

The military campaign is vulnerable to public opinion and public opinion is volatile - support for military action may be widespread but belief in its ability to deliver is not. Few, even among those who are prosecuting it at the highest level, believe that the current strategy is working. Both winter and Ramadan are approaching (the first bringing famine, the second fasting and diplomatic tension); the Americans are rapidly running out of things to bomb; they do not seem any closer to defeating the Taliban or catching Bin Laden, have no coherent strategy for what to do even if they do catch him or what kind of Afghanistan they would want to build after they have finished destroying it.

Every day produces many reasons to oppose this war from the pragmatic to the principled, the military to the moral. But the growing disillusionment with the war does not translate into the dedicated pursuit of peace without political intervention from the peace movement. Activists should look at what the Pentagon has been doing and then do the opposite: be honest in their motivation, clear in their objectives and non-dogmatic in their approach.